Difference between 3749578 and 3741636 crankcase vent tube brackets?
Can anyone tell me the difference between the 56 - E59 3749578 and L59-62 3741636 crankcase vent tube (road draft) lower brackets? Below is a pic of the late one from what I understand. According to my Assembly guide, this switchover happened 3-2-59 and is symbol 5. Anyone have a pic of the early one?
bracket_late.jpg
Further, the Judging Guide (JG) says about the crankcase (road draft) tube, that "Road draft tube outlet cut at an angle". Now also in my JG, I see that there are two part numbers for the road draft tube itself: Early 3726641 (3749684 optional), later replaced by 3737028 (3749580 optional). No date on this, but it is symbol 6, so probably happened after 3-2-59 in my mind. Pics below from Paragon who reproduces both.
tube_early.jpgtube_late.jpg
Anyone have any idea when this switchover happened? Also, more importantly, the two are shaped differently and the early tube outlet is NOT cut at an angle, while the late one is. Also, I can find all these numbers in my 1959 GM parts catalog. I would like to be NCRS correct, but it seems like the JG may be incorrect here? Anyone have pics of an early vs late tube aside from these?
bracket_late.jpg
Further, the Judging Guide (JG) says about the crankcase (road draft) tube, that "Road draft tube outlet cut at an angle". Now also in my JG, I see that there are two part numbers for the road draft tube itself: Early 3726641 (3749684 optional), later replaced by 3737028 (3749580 optional). No date on this, but it is symbol 6, so probably happened after 3-2-59 in my mind. Pics below from Paragon who reproduces both.
tube_early.jpgtube_late.jpg
Anyone have any idea when this switchover happened? Also, more importantly, the two are shaped differently and the early tube outlet is NOT cut at an angle, while the late one is. Also, I can find all these numbers in my 1959 GM parts catalog. I would like to be NCRS correct, but it seems like the JG may be incorrect here? Anyone have pics of an early vs late tube aside from these?
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